The Police Association says senior police detectives have raised doubts over the conviction of Teina Pora and it is calling for an independent inquiry.
Pora has spent 20 years in jail for the murder and rape of Susan Burdett in south Auckland in 1992, a crime he says he did not commit.
Police Association national president Greg O'Connor says a number of senior detectives with a good knowledge of the case are uncomfortable with Pora's conviction and the fact he is still in prison.
Mr O'Connor says there is sufficient concern to warrant an inquiry. He says the association is calling for the Minister of Justice to appoint someone independent to review the case.